In grasping an object, it is desirable for a hand to grasp the object with maximum amount of power, stability and precision over the movement of the object. This should be done while minimizing the fatigue in the digits, hand and arm resulting from such movements.
However, conventional grips or handles of implements are designed to have a mere bar-shape according to tradition rather than according to anatomical and physiological consideration. Thus, in grasping the gripping part or area of these implements, it has been impossible for the users to impartially, stably, and optimally use all the muscles of five digits, especially those of the thumb, index finger, and/or middle finger. In the description, the term "four fingers" denotes the second, third, fourth and fifth digit excluding the thumb.
In grasping an object, when all the flexors and adductors of the fingers hand, and arm are fully and stably activated in the similar manner as that for making a fist, the hand can grasp it with full power, firmness, accuracy and stability, and potential force can also be generated to the optimal.
When one makes a fist, the four fingers adduct to each other and flex into the palm, and the thumb also adducts, flexes, and wraps around the outside of the index and/or middle finger, and at this moment, all the flexors and adductors (see FIG. 2) of the fingers and hand are exerted to the optimal.
The mechanisms of movements of the flexors and adductors of the digits, hand, and arm are as follows.
In FIG. 4, the vector "a" denotes the force of the flexors of the thumb drawing the thumb to the palm and the vector "b" denotes the force of the adductors of the thumb drawing the thumb to the index finger. The letter "c" denotes the resultant force of vectors "a" and "b", and denotes the drawing force of the thumb to grasp the gripping part H.
Accordingly, in order to firmly grasp the gripping part H, the resultant force "c" of the thumb must be fully generated and exerted.
In FIG. 4, the vector "d" denotes the force of the flexors of the four fingers drawing the four fingers to the palm and the vector "e" denotes the force of adductors of the four fingers and the thumb exerting to one another. The letter "f" is the resultant force of vectors "d" and "e", and denotes the drawing force of the four fingers to grasp the gripping part H.
In order to firmly grasp the gripping part H, the resultant force "f" of the four fingers also must be fully generated and exerted.
Further, in order for a hand to grasp the gripping part H with full power and firmness, the resultant force "c" of the thumb and that "f" of the four fingers should be concentrated to a point or place as possible as can be.
Again in the right figure in FIG. 4, the letter "z" denotes the resultant force of vectors "c" and "f", and denotes the grasping force of the whole muscles in the digits, hand and arm to grasp the gripping part H.
In order to strongly, firmly, stably, and accurately grasp the gripping part H, said resultant force "z" must be fully generated and exerted.
In short, the resultant force of the thumb(vector "c") and the resultant force of the four fingers(vector "f") are so exerted as to be concentrated to and, encounter with each other at a point or place for the resultant force "z" to be fully generated and exerted.
FIG. 1 shows a right hand grasping the gripping part of a conventional bar-shaped handle of a certain implement.
When the four fingers wind around and grasp the gripping part H in the direction of arrow Q, the grasping force of the flexors of the four fingers is supported by the gripping part H but nothing except the thumb buttresses the grasping force of the adductors of the four fingers. Accordingly, the whole drawing force of the four fingers can not be fully generated and exerted.
In case of the thumb, it is bent in the direction of arrow P that is almost perpendicular to the direction Q of the locomotion of the four fingers. At this moment, the grasping force of the adductors of the thumb is supported by the gripping part H but nothing except the four fingers buttresses the grasping force of the flexors of the thumb, such that the whole drawing force of the thumb can not be fully generated and exerted.
Consequently, in order to more firmly grasp the gripping part H, the thumb is stick fast to, presses, or pushes the four fingers.
The very pressure or pushing of the thumb weakens the grasping force of the four fingers, let the four fingers loose stability and firmness, and, in turn, the unstable grasping force of the four fingers let the thumb more forcefully push the four fingers, which consequently makes the grasping power of the whole hand be weakened and unstable.
Further, as the digits and hand are normally more likely to slip with perspiration, the unstableness and slippage will grow much more when perspired.
In short, the structures of the conventional bar-shaped gripping parts have not been sufficient for the muscles in the digits and hand to be ultimately and harmoniously exerted, such that it has been difficult for the digits and hand to grasp the gripping part with full power, firmness, accuracy, and stability.
In order to overcome the deficiencies and shortcomings of the conventional bar-shaped gripping part of the handle of an implement, the present invention provides a finger supporting means T to the gripping part as shown in FIG. 3.
As shown in FIG. 4 that illustrates the procedure for a hand to grasp the gripping part H of an implement in FIG. 3.
as the drawing force of the flexors of the thumb (vector "a") is supported by the finger supporter T and the drawing force of the adductors of the thumb (vector "b") is supported by the gripping part H, the power of resultant force "c" of the thumb can be exerted to the optimal, and likewise,
as the drawing force of the flexors of the four fingers (vector "d") is supported by the gripping part H and the drawing force of the adductors of the four finger and those between the index finger and the thumb (vector "e") is supported by the finger supporter T, the power of resultant force "f" of the four fingers can be exerted to the optimal.
Accordingly, as the resultant force of the thumb(vector "c") and the resultant force of the four fingers(vector "f") are so exerted as to be concentrated to and encounter with each other at the finger supporter T, the resultant force "z" of the whole muscles of the digits and hand can be fully generated and exerted, such that one can grasp and control the gripping part H of the present invention with full strength, firmness, stability, and accuracy.